Gas barrier molded body and laminate using same

Abstract

A gas barrier molded body according to the present invention is formed from a resin composition including a resin material and an inorganic filler. The resin material is at least an ethylene-vinyl alcohol copolymer, and the inorganic filler is at least an inorganic layered compound. The inorganic layered compound is dispersed in the resin material having a content within a range of 3-15 mass% if the total amount of the resin composition is 100 mass%. Furthermore, the gas barrier molded body includes aggregated particles formed by aggregating the inorganic layered compound. In the aggregated particles, the resin material is interposed between the inorganic layered compounds adjacent to each other in the thickness direction. Thus, even better gas barrier properties are provided to the gas barrier molded body containing the ethylene-vinyl alcohol copolymer (EVOH) and the inorganic filler.

Description

Gas barrier molded article and laminate using the same

[0001] The present invention relates to a gas barrier molded article containing an ethylene vinyl alcohol copolymer (EVOH) and having good gas barrier properties, and a laminate including the gas barrier molded article in its laminate structure.

[0002] Conventionally, various types of gas barrier materials have been used in the field of packaging or covering items whose quality is significantly affected by contact with the outside air. Specific examples of gas barrier materials include those that have gas barrier properties themselves and those that achieve gas barrier properties as a composite material made by combining multiple materials.

[0003] For example, ethylene vinyl alcohol copolymer (EVOH) is known as a thermoplastic resin material having good gas barrier properties. EVOH has good physical properties such as solvent resistance, chemical resistance, transparency, aroma retention, and low thermal conductivity in addition to gas barrier properties, and is therefore used in a variety of packaging applications, as well as in containers for storing solvents, oils, and other chemical substances.

[0004] In order to further improve the gas barrier properties of EVOH, composite materials are also known in which EVOH is combined with other materials. A typical example is a composite material in which an inorganic filler is blended with EVOH (a resin composition containing EVOH and an inorganic filler). For example, Patent Document 1 discloses a resin composite in which a water-swellable layered inorganic compound is dispersed in EVOH.

[0005] In this EVOH resin composite, the EVOH has an ethylene content of 20 to 60 mol %, and the water-swellable layered inorganic compound contains a short particle component with a major axis of less than 0.2 μm and a long particle component with a major axis of 0.5 μm or more. Furthermore, the ratio of the short particle component is adjusted to 5 to 50%, and the ratio of the long particle component is adjusted to 20 to 50%. This EVOH resin composite is produced by mixing EVOH with a water content of 50% or more and the water-swellable layered inorganic compound, and then further mixing the mixture with EVOH.

[0006] Japanese Patent Application Laid-Open No. 2008-208327

[0007] The EVOH resin composite described in Patent Document 1 aims to improve gas barrier properties by limiting the ethylene content of the EVOH to a predetermined range and by containing a predetermined ratio of short particle components and long particle components in the water-swellable layered inorganic compound serving as the inorganic filler. However, in recent years, there has been a trend toward demand for even better gas barrier properties for gas barrier materials.

[0008] The present invention has been made to solve these problems, and an object of the present invention is to provide a gas barrier molded article containing an ethylene-vinyl alcohol copolymer (EVOH) and an inorganic filler with even better gas barrier properties.

[0009] In order to solve the above-mentioned problems, the gas barrier molding according to the present disclosure is a gas barrier molding formed from a resin composition containing a resin material and an inorganic filler, wherein the resin material is at least an ethylene-vinyl alcohol copolymer, the inorganic filler is at least an inorganic layered compound, the inorganic layered compound is dispersed in the resin material at a content in the range of 3 to 15 mass % when the total amount of the resin composition is taken as 100 mass %, and the gas barrier molding further contains agglomerated particles formed by agglomeration of the inorganic layered compound, and in the agglomerated particles, the resin material is interposed between adjacent inorganic layered compounds in the thickness direction.

[0010] In the above-described configuration, in a gas barrier molding containing an ethylene-vinyl alcohol copolymer as a resin material and an inorganic layered compound as an inorganic filler, the content of the inorganic layered compound is adjusted to be within a predetermined range, and in addition, some of the inorganic layered compound aggregates to form aggregated particles with the resin material interposed between them.

[0011] According to conventional common technical knowledge, it has been thought that it is important for inorganic fillers, particularly inorganic layered compounds, to disperse as "primary particles" in a resin material without agglomerating in order to exhibit gas barrier properties. However, in the gas barrier molded article according to the present disclosure, as described above, a portion of the inorganic layered compound aggregates to form "aggregated particles" with the resin material interposed therebetween, and it has been revealed that this makes it possible to achieve even better gas barrier properties than before.

[0012] Therefore, according to the above-mentioned configuration, it is possible to realize even better gas barrier properties in a gas barrier molded article containing an ethylene-vinyl alcohol copolymer and an inorganic layered compound.

[0013] The present disclosure also includes a laminate comprising the gas barrier molded article having the above-described configuration as a gas barrier layer.

[0014] According to the above configuration, the laminate has a gas barrier layer that is a gas barrier shaped article containing aggregated particles of an inorganic layered compound. Therefore, the laminate not only achieves better gas barrier properties, but also improves the gas barrier properties through a synergistic effect with other layers, or achieves other functions in addition to the gas barrier properties.

[0015] The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings.

[0016] The present invention, with the above-described configuration, has the effect of providing even better gas barrier properties in a gas barrier molded article containing ethylene vinyl alcohol copolymer (EVOH) and an inorganic filler.

[0017]

[0023] Figure 1A is a transmission electron microscope (TEM) image showing a typical structure of a gas barrier molded article according to the present disclosure, and Figure 1B is a TEM image showing a typical structure of aggregated particles contained in the gas barrier molded article shown in Figure 1A.

[0024] Figure 1B is a graph showing the relationship between the oxygen permeability index and the peak height at around 20° in the diffraction pattern of an X-ray diffraction (XRD) method for a typical example of a gas barrier molded article according to the present disclosure.

[0025] Figure 1C is a graph showing the relationship between the oxygen permeability index and the number of particles observed on the surface for a typical example of a gas barrier molded article according to the present disclosure.

[0026] Figure 5A is a graph showing the relationship between the oxygen permeability and the content of an inorganic layered compound for a typical example of a gas barrier molded article according to the present disclosure, and Figure 5B is a graph showing the relationship between the helium permeability and the content of an inorganic layered compound for a typical example of a gas barrier molded article according to the present disclosure.

[0027] Figure 5B is a graph showing the relationship between the oxygen permeability of the gas barrier molded article shown in Figure 5A and the helium permeability of the gas barrier molded article shown in Figure 5B.

[0018] The gas barrier molded article according to the present disclosure is formed from a resin composition containing a resin material and an inorganic filler, in which at least an ethylene vinyl alcohol copolymer (EVOH) is used as the resin material, and at least an inorganic layered compound is used as the inorganic filler. The inorganic layered compound among the inorganic fillers is dispersed in the resin material at a content in the range of 3 to 15 mass % when the total amount of the resin composition is taken as 100 mass %. Furthermore, the resin material contains agglomerated particles formed by agglomeration of the inorganic layered compound. In these agglomerated particles, the resin material is interposed between adjacent inorganic layered compounds in the thickness direction.

[0019] Representative embodiments of the present invention will be described below with reference to the drawings. Note that the same or corresponding elements will be designated by the same reference numerals throughout the drawings, and redundant description will be omitted.

[0020] [Resin Material] The gas barrier molded article according to the present disclosure is formed from the resin composition as described above. As described above, an example of the resin material contained in this resin composition is ethylene vinyl alcohol copolymer (EVOH).

[0021] As its name suggests, EVOH has a molecular structure in which ethylene units (-CHCH-) and vinyl alcohol units (-CH-CH(OH)-) are copolymerized as monomer units. The molar ratio of ethylene units among all the monomer units constituting EVOH (referred to as the "ethylene ratio" for convenience) is not particularly limited, but can generally be in the range of 3 to 90 mol%.

[0022] In particular, in the present disclosure, the lower limit of the ethylene ratio may be 20 mol% or more, 25 mol% or more, or 30 mol% or more. When the ethylene ratio is 20 mol% or more, the physical properties of the gas barrier molded article, such as moldability, gas barrier properties, and flexibility, can be improved. Furthermore, the upper limit of the ethylene ratio may be 70 mol% or less, 60 mol% or less, or 55 mol% or less.

[0023] Although it depends on the application or required physical properties of the gas barrier molded article according to the present disclosure, if the ethylene ratio of EVOH is too high, the gas barrier properties may be reduced. Furthermore, if the ethylene ratio of EVOH is too high, the melting point and glass transition temperature Tg of EVOH also tend to decrease. The molecular weight of EVOH is not particularly limited, and EVOH within a known range can be suitably used.

[0024] Furthermore, in the gas barrier molded article according to the present disclosure, the melt flow rate (MFR) of the EVOH is not particularly limited, but may be within a range of 0.5 to 100 g / 10 min according to ISO 1133 (190°C, load: 2,160 g), and may be within a range of 1.0 to 50 g / 10 min, or may be within a range of 1.5 to 10 g / 10 min. Depending on the application or required physical properties of the gas barrier molded article according to the present disclosure, if the MFR of the EVOH is too high, the mechanical strength of the resulting gas barrier molded article may be reduced. Furthermore, if the MFR is too low, processability may be reduced, potentially affecting the dispersion of the inorganic filler (inorganic layered compound) in the EVOH. Other properties of the EVOH, such as mechanical properties and thermal properties, are not particularly limited.

[0025] EVOH is generally produced by saponifying an ethylene-vinyl acetate copolymer, but the degree of saponification of the EVOH is not particularly limited in the present disclosure. Typically, the degree of saponification is 80 mol% or more, and may be 85 mol% or more, 90 mol% or more, or 98 mol% or more. Depending on the application or required physical properties of the gas barrier molded article according to the present disclosure, if the degree of saponification of the EVOH is too low, the gas barrier properties may be reduced.

[0026] In the gas barrier molded article according to the present disclosure, the EVOH may have, as monomer units, structural units other than ethylene units and vinyl alcohol units. The monomer compounds from which the other structural units are derived are not particularly limited, but specific examples include α-olefins such as propylene, isobutene, α-octene, α-dodecene, and α-octadecene; hydroxy group-containing α-olefins such as 3-buten-1-ol, 4-penten-1-ol, and 3-butene-1,2-diol; hydroxy group-containing α-olefin derivatives such as esters and acylation products of these hydroxy group-containing α-olefins; 3,4-diacetoxy-1-butene, 2,3-diacetoxy-1-allyloxypropane, 2-acetoxy-1-allyloxy-3-hydroxypropane, 3-acetoxy-1-allyloxy-2-hydroxypropane, 1,3- Examples include hydroxymethylvinylidene diacetates such as diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, and 1,3-dibutyryloxy-2-methylenepropane; glycerin monounsaturated alkyl ethers such as glycerin monoallyl ether, glycerin monovinyl ether, and glycerin monoisopropenyl ether; unsaturated carboxylic acids or their salts, partial or complete alkyl esters of unsaturated carboxylic acids, nitriles, amides, and anhydrides of unsaturated carboxylic acids, and other derivatives thereof; unsaturated sulfonic acids or their salts; vinylsilane compounds; vinyl chloride; styrene; and the like.

[0027] The EVOH may contain only one type of other structural unit derived from these monomer compounds, or two or more types in appropriate combination. The molar ratio of these other structural units is not particularly limited, and may be within a range that does not affect the characteristics of the EVOH or the physical properties required for the resulting gas barrier molded article.

[0028] Furthermore, regardless of whether or not the EVOH contains these other structural units, the EVOH may be modified (modified EVOH). The method for modifying the EVOH is not particularly limited, and examples thereof include known methods such as urethanization, acetalization, cyanoethylation, oxyalkylenation, and epoxidation.

[0029] In the gas barrier molded article according to the present disclosure, the resin material may be the above-mentioned EVOH alone, but other resin materials may also be used in combination. That is, in the gas barrier molded article according to the present disclosure, the resin material may consist of EVOH, or may be EVOH in combination with at least one other resin material.

[0030] Other resin materials that can be used in combination with EVOH are not particularly limited, but representative examples include known thermoplastic resins. Specific examples include polyethylene resins such as linear low-density polyethylene, low-density polyethylene, very low-density polyethylene, medium-density polyethylene, and high-density polyethylene; polyolefin resins other than polyethylene such as polypropylene, ethylene-propylene copolymer, propylene-α-olefin (α-olefin having 4 or more carbon atoms) copolymer, polybutene, and polypentene; modified polyolefin resins obtained by modifying these polyolefin resins; ethylene copolymers such as ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, and ethylene acrylate copolymer; polyester resins such as polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate; polyamide resins or copolymers thereof such as nylon 6, nylon 11, nylon 12, and nylon 66; polyvinyl chloride; polyvinylidene chloride; acrylic resins; polystyrene; vinyl ester resins; polycarbonate; halogenated polyolefins such as chlorinated polyethylene and chlorinated polypropylene; and various thermoplastic elastomer resins.

[0031] One or more of these other resin materials that can be used in combination with EVOH may be mixed together to form a polymer alloy, but other known combination methods may also be employed. The mixing ratio of the other resin materials to EVOH is not particularly limited, and it is sufficient that EVOH is substantially the main component of the resin materials that constitute the resin composition.

[0032] [Inorganic Filler] The inorganic filler contained in the resin composition that forms the gas barrier molded article according to the present disclosure may be at least an inorganic layered compound. As will be described later, the inorganic layered compound contributes to the exhibiting gas barrier properties of the gas barrier molded article by being dispersed in the resin material.

[0033] Specific examples of inorganic layered compounds include, but are not limited to, layered silicates such as clay minerals, synthetic hectorite, and modified bentonite; scaly (flake-like, thin-film-like) particles of metals or metal compounds such as aluminum flakes, iron oxide flakes, strontium titanate flakes, silver flakes, stainless steel flakes, and zinc flakes; metal foils such as aluminum foil, tin foil, bronze foil, nickel foil, and indium foil; and layered non-metallic inorganic compounds such as layered silica, hexagonal boron nitride, graphite, silicon flakes, and layered niobium titanate. These inorganic layered compounds may be used alone or in appropriate combinations of two or more.

[0034] In particular, in the present disclosure, clay minerals are preferably used as the inorganic layered compound.Specific clay minerals include, but are not limited to, 1:1 layer types such as lizardite, amesite, kaolinite, dickite, halloysite, and pyrophyllite; 2:1 layer types such as montmorillonite, stevensite, saponite, hectorite, beidellite, nontronite, sauconite, trioctahedral vermiculite, dioctahedral vermiculite, talc, phlogopite, biotite, lepidolite, illite, muscovite, paragonite, clintonite, margarite, clinochlore, chamosite, nimite, donbassite, cookeite (cookite), and sudoite; and misfit types such as antigorite, greenalite, and caryopilite (clintite can be classified as not only the 2:1 layer type but also the misfit type). These clay minerals may be used alone as the inorganic layered compound, or two or more kinds may be used in appropriate combination, or they may be used in appropriate combination with one or more kinds of inorganic layered compounds other than clay minerals.

[0035] In the present disclosure, a 2:1 layer clay mineral can be preferably used as the inorganic layered compound, and smectite is particularly preferably used. Smectite holds exchangeable cations between layers, and has the property of expanding the space between layers and swelling when water molecules are trapped between the layers by these interlayer cations. Specific examples of smectite include montmorillonite, stevensite, saponite, hectorite, beidellite, nontronite, and sauconite. These smectites may be used alone or in combination of two or more.

[0036] In this embodiment, among these smectites, at least one selected from the group consisting of montmorillonite, stevensite, saponite, and hectorite is preferably used. Typically, for example, a combination of montmorillonite and stevensite can be used, but it may also be montmorillonite alone, or only one other smectite, or a combination of montmorillonite and a smectite other than stevensite. The combination of smectites is not limited to two types, and may be three or more types.

[0037] When the inorganic layered compound is smectite, the type of interlayer cation is not particularly limited. Generally, the interlayer cation of smectite is sodium ion (Na + ), so in the present disclosure, it is sufficient that the smectite contains at least sodium ions as interlayer cations. In addition, in the present disclosure, the sodium ions of the smectite may be substituted with other cations. Examples of other cations that can be substituted include lithium ions (Li + ), proton (H + ) etc.

[0038] In the present disclosure, inorganic fillers other than inorganic layered compounds (other inorganic fillers) may be used in combination. Specific examples include inorganic salts such as calcium carbonate, antimony oxide, aluminum hydroxide, magnesium hydroxide, zinc borate, aluminum borate, red phosphorus, zinc carbonate, potassium titanate, calcium oxide, and magnesium oxide; mineral fillers such as talc, silica, mica, clay, shirasu balloon, wollastonite, and zeolite; glass fillers such as glass fiber, glass flakes, silica balloons, and glass balloons; inorganic fibers such as carbon fiber and fibrous gypsum; and other clay minerals such as activated clay, dawsonite, and hydrotalcite.

[0039] These other inorganic fillers are used for reinforcing resin materials, filling, insulating, and weight reduction, as well as for moisture absorption or gas adsorption. Many of these other inorganic fillers function as additives to the resin composition described below, and therefore, in the present disclosure, the other inorganic fillers may be considered as additives to the resin composition. Furthermore, the mineral fillers or other clay minerals may include those corresponding to inorganic layered compounds. In other words, the inorganic layered compounds in the present disclosure may also include those that function as additives to impart physical properties other than gas barrier properties.

[0040] In the present disclosure, an organic filler composed of an organic material may be used in addition to the inorganic filler. Examples of such organic fillers include, but are not limited to, cellulose, aramid fiber, and polyoxybenzoyl whisker.

[0041] [Resin Composition and Gas Barrier Molded Article] The gas barrier molded article according to the present disclosure is produced by preparing (manufacturing) a resin composition containing the above-mentioned resin material (at least EVOH is used) and inorganic filler (at least an inorganic layered compound is used), and molding the resin composition into a desired shape.

[0042] In the gas barrier molded article according to the present disclosure, the resin composition may contain known additives in addition to the resin material and inorganic filler. Representative additives include, but are not limited to, crystal nucleating agents, dispersants, colorants, antioxidants, antistatic agents, UV protection agents, plasticizers, light stabilizers, heat stabilizers, surfactants, antibacterial agents, desiccants, flame retardants, antifogging agents, and antiblocking agents. The blending amounts (contents) of these additives are also not particularly limited, and may be any amounts that do not impair the desired physical properties or functions, such as gas barrier properties, and that achieve the purpose of adding the additives (e.g., imparting physical properties, etc.) in the gas barrier molded article according to the present disclosure.

[0043] In the gas barrier molded article according to the present disclosure, a representative additive added to the resin composition is a dispersant. Specific types of dispersants are not particularly limited, but examples include polyorganic acids such as polyacrylic acid, polymethacrylic acid, sodium polyacrylate, ammonium polyacrylate, sodium polymethacrylate, ammonium polymethacrylate, sodium polycarboxylate, ammonium polycarboxylate, carboxylic acid copolymers, and sulfonic acid copolymers; sodium monophosphate, sodium diphosphate, sodium triphosphate, sodium pyrophosphate, sodium acid pyrophosphate, sodium tripolyphosphate, sodium tetrapolyphosphate, sodium hexametaphosphate, sodium acid hexametaphosphate, and phosphates thereof such as potassium salts, calcium salts, and magnesium salts; and the like. Alternatively, various commercially available dispersants can also be suitably used.

[0044] The resin composition according to the present disclosure can be molded into various shapes such as films, sheets, bags, fibers, containers, pipes, and housings, and these molded articles correspond to the gas barrier molded article according to the present disclosure. Furthermore, the resin composition according to the present disclosure can also be remolded by crushing, melting, kneading, etc., depending on the application of the molded article. In other words, the gas barrier molded article according to the present disclosure is recyclable.

[0045] The method for molding the resin composition of the present disclosure into, for example, a film, sheet, bag, or fiber is not particularly limited, and for example, uniaxial stretching or biaxial stretching can be used. Furthermore, the method for molding the resin composition of the present disclosure into, for example, a container, a pipe, a housing, or the like is also not particularly limited, and for example, methods such as extrusion molding, expansion extrusion molding, blow molding, and injection molding can be used. In other words, the method for manufacturing the gas barrier molded article according to the present disclosure is not particularly limited, and any manufacturing method can be used as long as the resin composition described above is molded into a desired shape by a known method.

[0046] Furthermore, when the resin composition according to the present disclosure is molded into a film, sheet, bag, or the like, it may of course be a single layer, or may be molded into a laminate in which it is laminated with other layers. That is, the gas barrier molded article according to the present disclosure may be configured as a laminate including, as a gas barrier layer, a resin composition containing at least EVOH and an inorganic layered compound. The specific configuration of the gas barrier molded article as a laminate is not particularly limited, and, for example, the other layer may be a layer of a known thermoplastic resin. Specific examples of the thermoplastic resin include the resins exemplified above as other resin materials that can be used in combination with EVOH.

[0047] The specific configuration of the laminate according to the present disclosure is not particularly limited. A typical example is a laminate having a three-layer structure including a protective film, a heat-sealing film, and a gas barrier film, with the gas barrier film sandwiched between the protective film and the heat-sealing film. Of the three-layer structure, the gas barrier film may be the gas barrier molded article according to the present disclosure. In other words, the gas barrier molded article can be formed into a film and laminated with other layers to form a laminate.

[0048] Another example is a four-layer laminate including a protective film, a heat-sealing film, and two gas barrier films, with the two gas barrier films sandwiched between the protective film and the heat-sealing film. One of the gas barrier films in this four-layer structure may be a gas barrier molded article according to the present disclosure. The other gas barrier film may be a gas barrier film having a different configuration from the gas barrier molded article according to the present disclosure, such as a metal foil, a vapor-deposited film, or a film in which a known coating treatment has been applied to the surface of the vapor-deposited film.

[0049] The laminate according to the present disclosure has the gas barrier molded article according to the present disclosure as a gas barrier layer, and therefore the laminate can achieve even better gas barrier properties. Furthermore, in the above-described configuration example, the laminate includes a heat-sealing film, and therefore the laminate can achieve heat-sealing properties as well as gas barrier properties. Furthermore, in the four-layer laminate among the above-described configuration examples, the gas barrier layer includes the gas barrier molded article according to the present disclosure and a gas barrier layer of another configuration, and therefore the gas barrier properties of the laminate can be further improved.

[0050] Therefore, in the laminate according to the present disclosure, by having the gas barrier molded article according to the present disclosure as a gas barrier layer, it is possible to improve the gas barrier properties through a synergistic effect with other layers, or to achieve other functions in addition to the gas barrier properties.

[0051] As described above, the gas barrier molded article according to the present disclosure is produced by molding a resin composition into a desired shape, but the present disclosure does not particularly limit the method for producing the resin composition. Generally, the resin composition according to the present disclosure can be produced by kneading a resin material mainly composed of EVOH, an inorganic filler mainly composed of an inorganic layered compound, and other components as necessary using a known method.

[0052] A representative example of a method for producing a resin composition according to the present disclosure is a method in which EVOH is adjusted to a water content within a desired range, an aqueous dispersion of an inorganic layered compound (clay liquid) is blended with the EVOH, the resulting mixture is melt-kneaded, and the water content of the kneaded mixture is reduced to a desired range during the kneading process. More specifically, examples of the methods for producing a resin composition include those described in Reference 1: JP 2002-284887 A or Reference 2: JP 2006-052351 A.

[0053] The kneading device used to knead the resin material and inorganic filler is not particularly limited, and known single-screw kneaders or twin-screw kneaders can be suitably used. The method for preparing the aqueous dispersion of the inorganic filler is also not particularly limited, and known mixers, blenders, homogenizers, etc. can be used. The content of the inorganic filler (inorganic layered compound) contained in the aqueous dispersion is also not particularly limited. Generally, the solids concentration can be in the range of 1 to 15% by mass. Depending on the specific composition of the aqueous dispersion, a solids concentration exceeding 15% by mass may significantly reduce fluidity. Furthermore, the aqueous dispersion may contain a solvent other than water, or may contain additional components such as a dispersant, as necessary.

[0054] In the gas barrier molded article according to the present disclosure, as described below, an inorganic layered compound is dispersed in a resin material mainly composed of EVOH, and the inorganic layered compound is dispersed in the resin material as agglomerated particles. In these agglomerated particles, the resin material (EVOH, etc.) is interposed between adjacent inorganic layered compound particles in the thickness direction. Therefore, it is thought that the inorganic layered compound dispersed in the dispersion may re-aggregate during kneading.

[0055] In the present disclosure, the specific conditions for re-aggregating the inorganic layered compound are not particularly limited, and the production conditions may be adjusted appropriately depending on the type or physical properties of the EVOH resin material, the type or physical properties of the inorganic layered compound, the specific configuration of the kneading device, etc.

[0056] For example, blending an inorganic filler in EVOH as an aqueous dispersion allows for more uniform dispersion than blending the inorganic filler directly as a powder, and it is known that dispersing a water-swellable inorganic layered compound in water promotes layer peeling (or cleavage) (Reference 1). Therefore, it is believed that by appropriately adjusting the conditions for preparing the aqueous dispersion and the conditions for blending the aqueous dispersion into EVOH, it is possible to achieve good dispersion of the inorganic layered compound in EVOH during kneading. When preparing the aqueous dispersion, for example, a known mixer, blender, homogenizer, or the like may be used, or a high-pressure dispersion device, ball mill, ultrasonic treatment device, or the like may also be used.

[0057] It is believed that continued kneading thereafter causes the inorganic layered compound dispersed in the EVOH to re-aggregate, thereby forming the aggregated particles in the gas barrier molded article according to the present disclosure. Therefore, it is believed that by appropriately adjusting the kneading conditions after blending (adding) the inorganic layered compound in the kneading device or the physical properties such as the resin viscosity during kneading, it is possible to re-aggregate the dispersed inorganic layered compound.

[0058] When producing the resin composition according to the present disclosure, the compounding ratio of the resin material and the inorganic filler, i.e., the contents of the resin material and the inorganic filler in the gas barrier molded article, are not particularly limited, but from the viewpoint of realizing good gas barrier properties due to the inorganic filler, the content of the inorganic filler may be in the range of 3 to 15 mass% when the total amount of the resin composition is taken as 100 mass%. If the content of the inorganic filler is less than 3 mass%, it may be difficult to achieve good gas barrier properties in the resulting gas barrier molded article. If the content of the inorganic filler exceeds 15 mass%, it may be difficult to disperse the inorganic layered compound well in the resin material.

[0059] From the viewpoint of dispersing the inorganic layered compound in the resin composition more satisfactorily, the content of the resin material may be in the range of 97 to 85% by mass when the total amount of the resin composition is taken as 100% by mass. In the present disclosure, since at least EVOH is used as the resin material, if the total amount of the resin composition is taken as 100% by mass and only EVOH is used as the resin material, the content of EVOH in the resin composition can be in the range of 97 to 85% by mass.

[0060] Furthermore, in addition to the inorganic layered compound, the other inorganic fillers described above can also be used as the inorganic filler. From the viewpoint of realizing even better gas barrier properties, it is sufficient that the content of the inorganic layered compound used as the inorganic filler is in the range of 3 to 15 mass % when the total amount of the resin composition is taken as 100 mass %.

[0061] The lower limit of the content of the inorganic filler (or inorganic layered compound) may be 3% by mass or more, 4.5% by mass or more, or 6% by mass or more. On the other hand, the upper limit of the content of the inorganic filler (or inorganic layered compound) may be 15% by mass or less, 13% by mass or less, or 12% by mass or less. Herein, in this specification, the upper limit or lower limit of a numerical range including the content of the inorganic filler or the like can be changed from "below" to "less than," and the lower limit can be changed from "below" to "more than," as long as it does not deviate from the gist of the numerical range.

[0062] If the inorganic filler content is less than 3% by mass, the labyrinth effect may be insufficient, and the gas barrier molding may not achieve sufficient gas barrier properties, depending on conditions such as the type of inorganic filler (particularly the inorganic layered compound) or the composition of the resin composition. On the other hand, if the inorganic filler content exceeds 15% by mass, the production rate of the gas barrier molding may be slowed, or the aggregated particles of the inorganic filler (inorganic layered compound) may become large, affecting the appearance of the gas barrier molding, depending on conditions such as the type of inorganic filler or the composition of the resin composition. Note that, although depending on the above conditions, a decrease in production rate or an effect on the appearance tends to gradually become noticeable when the inorganic filler content exceeds about 13% by mass.

[0063] Here, the content of inorganic filler (inorganic layered compound) is substantially equal to the amount blended during production of the resin composition or gas barrier molded article, but can also be evaluated, for example, by analyzing the ash content of the resin composition or gas barrier molded article. Representative methods for ash content analysis include the methods used in the Examples described below. For the measurement or evaluation methods of numerical values ​​or evaluation values ​​described in this embodiment, including this ash content analysis, the methods described in the Examples described below are preferably used. Furthermore, since the measurement or evaluation methods of numerical values ​​or evaluation values ​​not described in the Examples are well known, methods described in patent documents corresponding to the technical fields of the present disclosure can be used.

[0064] As described above, a dispersant is a typical additive in the gas barrier molded article according to the present disclosure, but the specific content of the dispersant is not particularly limited. Typically, the content of the dispersant may be in the range of 0.015 to 1.5% by mass, where the total amount of the resin composition is taken as 100% by mass. The content of the dispersant is more preferably in the range of 0.06 to 0.75% by mass.

[0065] In the present disclosure, when a dispersant is added to a resin composition, a method of adding the dispersant to the aqueous dispersion (clay liquid) described above can be mentioned. If the content of the dispersant is too low below the above range, it becomes difficult to obtain the viscosity reducing effect of the aqueous dispersion (clay liquid), and the dispersion of the clay in the aqueous dispersion (clay liquid) tends to be insufficient. On the other hand, if the amount of dispersant added is too high above the above range, it has a large effect on the resin material constituting the resin composition, and for example, when the resin composition is molded into a sheet, the thickness tends to be unstable.

[0066] [Aggregated Particles] In the gas barrier molding according to the present disclosure, as described above, the inorganic filler (or inorganic layered compound) is dispersed in the resin material (or EVOH) at a content in the range of 3 to 15 mass % when the total amount of the resin composition is taken as 100 mass %, and the inorganic layered compound dispersed in the resin material contains aggregated particles formed by aggregation of the inorganic layered compound.

[0067] Fig. 1A shows a transmission electron microscope (TEM) photograph (TEM photograph) of one example of a gas barrier molded article according to the present disclosure, and Fig. 1B shows an enlarged photograph of a portion of the TEM photograph shown in Fig. 1A. As shown in Fig. 1A, when the gas barrier molded article is enlarged, "particles" of smectite (specifically, montmorillonite) as an inorganic layered compound are dispersed in EVOH, which is a resin material, and the dispersed layered smectite "particles" vary in thickness, ranging from thin to thick.

[0068] As shown in Fig. 1B, which is an enlarged view of a thicker (larger) "granule," in this "granule," many smectite particles are aggregated so as to overlap each other, and EVOH is interposed between adjacent smectite particles in the thickness direction. In other words, the thick "granule" is composed of aggregated particles formed by aggregation of multiple smectite particles.

[0069] If the smectite aggregated particles were initially aggregated after being blended (added) to EVOH (a resin material), EVOH would not be present between adjacent smectite particles in the thickness direction, and spaces would be formed between the smectite particles. However, in the gas barrier molded article according to the present disclosure, as shown in Figure 1B, EVOH is present between the smectite particles, rather than spaces. Therefore, the thick "granules" are considered to be aggregated particles that were formed during the manufacturing process after the smectite (inorganic layered compound) was once well dispersed.

[0070] When inorganic layered compounds such as smectite are well dispersed in a resin material, the so-called "maze effect" slows down gas diffusion, and the resulting gas barrier molded article achieves good gas barrier properties. On the other hand, if the inorganic layered compounds aggregate in the resin material, the "maze effect" cannot be fully exerted, and the gas barrier properties will be reduced.

[0071] However, in the gas barrier molded article according to the present disclosure, even though the inorganic layered compound is aggregated to form aggregated particles, it is possible to exhibit good gas barrier properties, as will be shown in the examples described below. The reason for this is not clear at present, but it is thought that the inorganic layered compound that was once dispersed in the resin material "reagglomerates" to form aggregated particles, and the resin material is interposed between adjacent inorganic layered compounds in the thickness direction, resulting in a maze effect derived from the aggregated particles, which may result in good gas barrier properties.

[0072] Here, based on the observation results of the TEM photographs shown in Figures 1A and 1B, it has become clear that in the gas barrier molded body according to the present disclosure, there are better ranges for the thickness of the resin material interposed between the inorganic layered compounds constituting the aggregated particles, as well as for the thickness of the resin material interposed between adjacent "granules."

[0073] In the gas barrier molding according to the present disclosure, the "particles" present in the resin material include both inorganic layered compounds that are dispersed without agglomeration in the resin material and aggregated particles formed by agglomeration of these compounds. Therefore, for convenience, the inorganic layered compounds that are dispersed without agglomeration are referred to as "non-aggregated particles," and the non-aggregated particles and aggregated particles are collectively referred to as "inorganic particles." In this case, the thickness of the resin material present between adjacent inorganic particles is preferably 100 nm or more and 1000 nm or less. Furthermore, the thickness of the resin material interposed between adjacent inorganic layered compounds in the aggregated particles is preferably 1 nm or more and 10 nm or less.

[0074] Adjacency of inorganic particles can be classified into three types: adjacency between non-aggregated particles, adjacency between non-aggregated and aggregated particles, and adjacency between aggregated particles. In the present disclosure, regardless of whether the inorganic particles present in the resin material are non-aggregated or aggregated, the inorganic particles can be considered to be well dispersed throughout the resin material by having the spacing between these inorganic particles be 100 nm to 1000 nm. This is thought to enable the inorganic particles to effectively achieve a maze effect regardless of whether they are non-aggregated or aggregated.

[0075] On the other hand, when focusing on agglomerated particles, it is thought that the maze effect resulting from the agglomerated particles can be effectively achieved if the spacing between the re-aggregated inorganic layered compounds is within the range of 1 nm to 10 nm. Therefore, even better gas barrier properties can be achieved by producing a resin composition and then producing a gas barrier molded article such that the thickness of the resin material present between the inorganic particles and the thickness of the resin material present between the inorganic layered compounds that make up the agglomerated particles are within the above ranges.

[0076] Furthermore, based on the observation results of the TEM photographs shown in Figures 1A and 1B, it has become clear that in the gas barrier molded article according to the present disclosure, the aggregated particles can be classified into three types based on their size, and that if the abundance ratio of these types is within a predetermined range, it may be possible to achieve better gas barrier properties.

[0077] 1A , a TEM photograph shows that aggregate particles can be classified into small aggregate particles having a major axis of less than 0.2 μm, intermediate aggregate particles having a major axis of 0.2 μm or more and 0.5 μm or less, and large aggregate particles having a major axis of more than 0.5 μm. In the gas barrier molded article according to the present disclosure, the content of intermediate aggregate particles among these three types of aggregate particles is preferably 37% or more and 60% or less. It is believed that if the content of intermediate aggregate particles (or the abundance ratio of intermediate aggregate particles among all aggregate particles) is within this range, the labyrinth effect resulting from the aggregate particles can be more efficiently realized.

[0078] [Gas barrier properties] As described above, in the gas barrier molded article according to the present disclosure, the inorganic layered compound re-aggregates to form aggregated particles, thereby realizing unexpectedly good gas barrier properties. Furthermore, in the present disclosure, in addition to the inclusion of aggregated particles, the crystallization of EVOH, which is the main component of the resin material, also contributes to the gas barrier properties.

[0079] Specifically, in the gas barrier molded article according to the present disclosure, the peak height at about 20° (for convenience, referred to as the "20° peak height") in the diffraction pattern obtained by X-ray diffraction (XRD) may be 5000 CPS or more.

[0080] The peak height in an XRD diffraction pattern generally corresponds to the degree of crystallization (or the amount of crystals), with the maximum peak of EVOH occurring around 20°. The height of this maximum peak attributable to EVOH serves as an index for evaluating the crystallinity of EVOH. As shown in the examples described below, when the 20° peak height is 5000 CPS or more, the gas barrier molded article can effectively suppress oxygen permeation (see Figure 2). Therefore, when the 20° peak height is 5000 CPS or more, it can be determined that the EVOH constituting the gas barrier molded article is well crystallized.

[0081] Furthermore, when observing the surface of the gas barrier molded article according to the present disclosure, particles having a diameter of 7 μm or more may be observed. These particles are observed in response to the crystallization of EVOH, and as long as the particle diameter is at least 7 μm or more, the gas barrier molded article can effectively suppress oxygen permeation. Furthermore, in the gas barrier molded article according to the present disclosure, the number of particles having a diameter of 7 μm or more is 40,000 particles / cm. 2 As shown in the examples below, the number of particles of 7 μm or more may be observed in 1 cm 2 Winning 4 x 10 4 If the number is equal to or more than 1, the gas barrier molded article can effectively suppress oxygen permeation (see FIG. 3).

[0082] Furthermore, the gas barrier molded article according to the present disclosure may have a haze of 10% or more and 60% or less. Generally, the haze of a resin material is used as an index representing the degree of cloudiness or the degree of light scattering in the resin material. The lower the haze, the higher the transparency of the resin material. It is known that the haze value is affected by the components (particularly fillers, etc.) contained in the resin material or the crystallization of the resin material.

[0083] As shown in the examples described below, in the present disclosure, oxygen permeation can be effectively suppressed if the haze of the gas barrier molding is within the range of 10% to 60% (see FIG. 4). Therefore, if the haze of the gas barrier molding is 10% or more, it can be considered that the inorganic layered compound is well dispersed in the EVOH, or that the EVOH is well crystallized. Furthermore, if the haze of the gas barrier molding is 60% or less, it can be considered that the amount of inorganic layered compound contained in the resin composition is not excessive compared to the EVOH, or that the EVOH is not excessively crystallized.

[0084] Although there are no particular limitations on the evaluation of the gas barrier properties of the gas barrier molded article according to the present disclosure, a representative example is oxygen permeability. Specifically, in the present disclosure, when the thickness of the gas barrier molded article is 100 μm, the oxygen permeability is 0.03 cc / m under an environment of 23° C. and a relative humidity of 60%. 2If the gas barrier strength is equal to or less than 1000 kJ / day·atm, the gas barrier molded article can be judged to have good gas barrier properties (see FIG. 5A).

[0085] In the examples described later, the gas barrier properties of the gas barrier molded article are evaluated using an oxygen permeability index based on this oxygen permeability. Specifically, the oxygen permeability index is defined as the ratio of the oxygen permeability of EVOH (a resin material containing an inorganic filler, i.e., a resin composition) after kneading with an inorganic layered compound to the oxygen permeability of EVOH (a resin material containing no inorganic filler) before kneading with the inorganic layered compound (inorganic filler).

[0086] For example, if the oxygen permeability of EVOH containing no inorganic layered compound is represented as TR0, the oxygen permeability of a resin composition (or gas barrier molded article) in which the inorganic layered compound is dispersed in EVOH is represented as TR1, and the oxygen permeability index is represented as ITR, then ITR can be expressed as ITR = TR1 / TRO. If the oxygen permeability index of any gas barrier molded article is 1.0, it has the same oxygen permeability as a resin material containing no inorganic filler, and the smaller the oxygen permeability index is below 1.0, the more difficult oxygen permeates, i.e., the higher the gas barrier property can be determined to be. In the examples described below, it is determined that good gas barrier property can be achieved when the oxygen permeability index is 0.5 or less.

[0087] In the gas barrier molded article according to the present disclosure, the gas barrier property can be evaluated not only by oxygen permeability but also by helium permeability. Specifically, in the present disclosure, when the thickness of the gas barrier molded article is set to 100 μm, the helium permeability is 55 cc / m under an environment of 40° C. and 0% relative humidity. 2 If the gas barrier strength is equal to or less than 1000 kJ / day·atm, the gas barrier molded article can be judged to have good gas barrier properties (see FIG. 5B).

[0088] Furthermore, as shown in the examples described below, a good proportional relationship can be confirmed between the oxygen permeability and the helium permeability of the gas barrier molded article according to the present disclosure (see Figure 6). In other words, the gas barrier molded article according to the present disclosure not only effectively prevents the permeation of oxygen, which is highly reactive even in the open air (atmosphere), but also effectively prevents the permeation of helium, which has a molecular (atomic) size significantly smaller than that of oxygen, and a proportional relationship is essentially established in which the lower the oxygen permeability, the lower the helium permeability.

[0089] Therefore, it is believed that the gas barrier molded article according to the present disclosure has a substantially proportional relationship in permeability not only to oxygen and helium but also to other gas components, and therefore is capable of exhibiting good gas barrier properties for all gas components.

[0090] As described above, the gas barrier molding according to the present disclosure is formed from a resin composition containing a resin material and an inorganic filler, wherein the resin material is at least an ethylene-vinyl alcohol copolymer, and the inorganic filler is at least an inorganic layered compound. Furthermore, the inorganic layered compound in the inorganic filler is dispersed in the resin material at a content ranging from 3 to 15 mass % when the total amount of the resin composition is taken as 100 mass %. Furthermore, the gas barrier molding according to the present disclosure contains aggregated particles formed by aggregation of the inorganic layered compound, and in the aggregated particles, the resin material is interposed between adjacent particles of the inorganic layered compound in the thickness direction.

[0091] According to conventional common technical knowledge, it has been thought that it is important for inorganic fillers, particularly inorganic layered compounds, to be dispersed as "primary particles" in a resin material without agglomerating in order to exhibit gas barrier properties. However, in the gas barrier molded article according to the present disclosure, a portion of the inorganic layered compound aggregates with the resin material interposed therebetween to form "aggregated particles," which has been found to enable even better gas barrier properties to be realized. By having such a configuration, the gas barrier molded article according to the present disclosure is able to achieve even better gas barrier properties.

[0092] The present disclosure will be described in more detail based on representative examples, but the present invention is not limited thereto. Those skilled in the art can make various changes, modifications, and alterations without departing from the scope of the present invention.

[0093] (Gas barrier molded article sample) In this example, the resin material had an ethylene ratio of 32 mol%, a melt flow rate (MFR) of 1.7 g / min (ISO1133 (190°C, load: 2160 g)), and an oxygen permeability of 0.06 cc / m 2 EVOH (manufactured by Kuraray Co., Ltd., product name: EVAL J171B) having a viscosity of 100 μm / day / atm (thickness: 100 μm, 23° C., 60% RH) was used, and smectite (montmorillonite), an inorganic layered compound, was used as the inorganic filler.

[0094] Agglomerated smectite with a particle size of several hundred micrometers was placed in water and thoroughly stirred to disintegrate the smectite. This resulted in a thorough dispersion of the smectite in water, preparing an aqueous smectite dispersion (clay liquid). The smectite content was approximately 9% by mass in terms of solids concentration.

[0095] EVOH was charged into a single-screw kneader and melt-kneaded, while the clay liquid was further blended and melt-kneading continued. During melt-kneading, water, which served as the solvent (dispersion medium) for the clay liquid, was appropriately evaporated to adjust the moisture content of the kneaded mixture, so that the moisture content of the kneaded mixture (resin composition) discharged from the kneader was within the range of 0.1 to 5 mass%. The resin composition extruded from the single-screw kneader was molded into a sheet using a T-die to prepare a gas barrier molded article sample according to this example. In this example, the mixing ratio (compounding ratio) of EVOH to smectite was adjusted within the range of 100:0 to 90:10, and multiple types of samples were produced.

[0096] The smectite content (content, addition rate, or blending rate of inorganic filler or inorganic layered compound) in the gas barrier molded article samples according to the present invention was evaluated by the ash analysis described below. The content of the inorganic layered compound corresponds to the mass % when the total mass of the resin composition is taken as 100 mass %.

[0097] In the ash analysis in this example, the pre-dried sample was placed in a crucible, the initial mass (unit: g) was measured, and the crucible was heated with a nichrome wire stove in an exhaust system. Next, the crucible was placed in an electric furnace (manufactured by Isuzu Motors Ltd., product name: AT-S13) and heated at 600°C for 3 hours.

[0098] The crucible was then placed in a desiccator and cooled to room temperature, after which the mass (unit: g) after weight loss was measured and the ash content was calculated using the following formula (1). The achievement rate relative to the target ash content was calculated using the following formula (2) from the ratio of the target ash content (unit: mass%) to the measured ash content (unit: mass%) obtained using formula (1). Ash content [mass%] = (initial mass - mass after weight loss) ÷ initial mass × 100 (1) Achievement rate [mass%] = measured ash content ÷ target ash content × 100 (2)

[0099] (Evaluation of Aggregated Particles) The aggregated particles contained in the gas barrier molded body samples according to the present examples were evaluated based on observation using a field emission analytical transmission electron microscope FE-TEM (manufactured by Hitachi High-Tech Corporation, product name: HE-2200) and analysis of photographed images (TEM images).

[0100] The thickness of the resin material present between adjacent inorganic particles (aggregated particles or non-aggregated particles) and the thickness of the resin material interposed between adjacent inorganic layered compounds in the aggregated particles were measured and evaluated by observation with an FE-TEM.

[0101] The diameter of the aggregated particles and the classification of small aggregated particles, medium aggregated particles, and large aggregated particles were evaluated by processing TEM images taken with the FE-TEM.

[0102] Specifically, first, the film angle of a 15,000x TEM image was adjusted using Photoshop CS2 (Adobe Inc.), and the image was adjusted to a horizontal angle using a magnification that allowed the sample surface to be confirmed, to prepare an image for analysis. Next, Image J (open source software) was used to perform binarization and filtering on the image for analysis, and the number, major axis, minor axis, aspect ratio, and major axis angle of the aggregated particles contained in the TEM image were measured.

[0103] FIG. 1A shows a TEM image illustrating an example of agglomerated particles and non-agglomerated particles (inorganic particles) in a gas barrier molded body sample according to this example, and FIG. 1B shows a TEM image illustrating an example of the agglomerated state of the agglomerated particles and the presence of resin material between the agglomerated particles.

[0104] Observation and analysis of TEM images revealed that in the gas barrier molded article sample according to this example, the inorganic layered compound (smectite), which was supposed to have been sufficiently dispersed in advance as an aqueous dispersion (clay liquid), formed aggregated particles, as shown in Figure 1A. Furthermore, it was also revealed that in these aggregated particles, a resin material was interposed between adjacent inorganic layered compounds in the thickness direction, as shown in Figure 1B. Therefore, it is believed that the inorganic layered compound that was dispersed beforehand re-aggregated during melt-kneading, resulting in the formation of a layer of resin material between the inorganic layered compounds.

[0105] 1A, it was revealed that in the gas barrier molded product sample of this example, not all of the inorganic layered compound (smectite) was re-aggregated, and that non-aggregated particles that were dispersed without aggregating were also present in the resin material. Here, when non-aggregated particles and aggregated particles were collectively included as inorganic particles, the analysis results of the TEM images revealed that in gas barrier molded product samples with good gas barrier properties, the thickness of the resin material present between adjacent inorganic particles was in the range of 100 nm to 1000 nm.

[0106] Furthermore, the results of the TEM image analysis also revealed that in gas barrier molded body samples with good gas barrier properties, the thickness of the resin material interposed between adjacent inorganic layered compounds in the contained aggregated particles was in the range of 1 nm or more and 10 nm or less.

[0107] Furthermore, analysis of the TEM images revealed that the size of the agglomerated particles was not generally uniform but varied. Therefore, when the agglomerated particles were classified into small agglomerated particles with a long axis of less than 0.2 μm, medium agglomerated particles with a long axis of 0.2 μm to 0.5 μm, and large agglomerated particles with a long axis of more than 0.5 μm, it was revealed that the content of medium agglomerated particles was 37% to 60% in gas barrier molded product samples with good gas barrier properties.

[0108] (Crystallization of EVOH) The crystallinity of the EVOH in the gas barrier molded article sample according to this example was evaluated by XRD (X-ray diffraction).

[0109] First, a small amount of vacuum grease was placed in four spots on a non-reflective sample holder, and a sample (thickness: 80 μm (±10 μm)) cut to approximately 15 mm square was placed on top of it and gently pressed down to fix it in place. Next, the non-reflective sample holder was set in an XRD device (manufactured by Rigaku Co., Ltd., product name: MiniFlex600, radiation source: Cu), and the diffraction pattern was measured under the following optical element conditions and measurement conditions.

[0110] The optical conditions were as follows: incident Soller slit: Soller (inc) 2.5°, IHS: 10.0 mm, DS: 1.25°, SS: 8.0 mm; receiving Soller slit: Soller (rec) 2.5°, RS: 13.0 mm (open); monochromator: Kβ filter (×1). The measurement conditions were: start: 2.0°, end: 30.0°, step: 0.02°, speed: 5.0° / min, tube voltage: 30 kV, tube current: 5 mA.

[0111] The relationship between the peak height at around 20° in the diffraction pattern of each gas barrier molded article sample obtained and the oxygen permeability index is shown in Figure 2. As mentioned above, the oxygen permeability index can be expressed as ITR = TR1 / TRO, where TR0 is the oxygen permeability of EVOH that does not contain an inorganic layered compound (smectite in this example), TR1 is the oxygen permeability of a gas barrier molded article (resin composition) in which the inorganic layered compound is dispersed in EVOH, and ITR is the oxygen permeability index.

[0112] In Figure 2, the vertical axis represents the oxygen permeability index, and the horizontal axis represents the peak height (unit: CPS) around 20° in the XRD diffraction pattern. The maximum peak of EVOH occurs around 20° in the XRD diffraction pattern (the "20° peak height" mentioned above), which serves as an index for evaluating the crystallinity of EVOH. Also, in Figure 2, a thick dotted line indicates an oxygen permeability index of 0.5, which is the upper limit index for good gas barrier property in the present disclosure, and a thick dotted line indicates a 20° peak height of 5000 CPS. As is clear from the results in Figure 2, a gas barrier molded article sample can achieve an oxygen permeability index of 0.5 or less if the 20° peak height is 5000 CPS or more.

[0113] (Particles on the Surface of Gas Barrier Molded Article) In the gas barrier molded article sample according to this example, the particles observed on the surface and the number thereof were evaluated and measured by observation using a microscope.

[0114] First, a microscope (Keyence Corporation, product name: VHX-6000) was used to photograph the surface of a sample (thickness: 80 μm (±10 μm)) at a magnification of 30 times. Next, the microscope's measurement and scale function - automatic area measurement (particle count) was used to distinguish particles in the photographed image from the brightness difference, and the number of particles was automatically calculated. At this time, the threshold correction was 0, and no hole filling or small particle removal settings were set. In addition, in the automatic calculation of the number of particles, a particle count was calculated for an area of ​​1 cm 2 The numbers were converted to represent the number of hits.

[0115] The relationship between the number of particles observed in each gas barrier molded article sample and the oxygen permeability index is shown in Figure 3. In Figure 3, the vertical axis represents the oxygen permeability index, and the horizontal axis represents the number of particles (unit: particles / cm 2) On the horizontal axis, a thick line indicates every 100,000 particles, and a thin line indicates every 20,000 particles. In addition, in FIG. 3 , as in FIG. 2 , an oxygen permeability index of 0.5 is indicated by a thick dotted line, and a particle count of 40,000 is indicated by a thick dotted line. As is clear from the results in FIG. 3 , in gas barrier molded body samples that achieve an oxygen permeability index of 0.5 or less, particles with a diameter of 7 μm or more are observed on the surface, and in particular, when the particle count exceeds 40,000, the gas barrier molded body sample is more likely to achieve an oxygen permeability index of 0.5 or less.

[0116] (Haze) The haze of the gas barrier molded article sample according to this example was measured in accordance with JIS K7136 using a haze meter (manufactured by Suga Test Instruments Co., Ltd., product name: HZ-V3) under the measurement conditions of double beam system, light source: D65 light, measurement hole diameter: φ20 mm, sample thickness: 80 μm (±10 μm).

[0117] The relationship between the measured haze value and the oxygen permeability index for each gas barrier molded article sample is shown in Figure 4. In Figure 4, the vertical axis represents the oxygen permeability index, and the horizontal axis represents the haze (unit: %). In Figure 4, as in Figures 2 and 3, an oxygen permeability index of 0.5 is indicated by a thick dotted line, and hazes of 10% and 60% are indicated by thick dotted lines. As is clear from the results in Figure 4, if the haze is 10% or more and 60% or less, the gas barrier molded article sample is more likely to achieve an oxygen permeability index of 0.5 or less.

[0118] (Oxygen Permeability) The oxygen permeability of the gas barrier molded article sample according to this example was measured using a coulometric oxygen permeability measuring device (manufactured by MOCON Inc., product name: OX-TRAN 22 / 2L).

[0119] First, a sample was placed in the cell of the measuring device, and a permeation area of ​​50 cm 2The oxygen permeability was measured under the measurement conditions of 23°C, 60% RH (relative humidity), and a measurement lower limit of 0.01. Thereafter, the sample was removed from the measurement device, and the thickness of the sample was measured. The oxygen permeability calculated by the measurement device was then converted to a thickness of 100 μm. This was done to eliminate the influence of variations in sample thickness and compare oxygen permeabilities at the same thickness, since oxygen permeability is inversely proportional to thickness.

[0120] FIG. 5A shows the relationship between oxygen permeability and the content of inorganic layered compound for a comparative sample of a gas barrier molded article made only of EVOH without containing inorganic layered compound (smectite), and three types of gas barrier molded article samples with different contents (addition rate, blending rate) of inorganic layered compound. In FIG. 5A, the vertical axis represents oxygen permeability (unit: cc / m 2 The horizontal axis represents the content of the inorganic layered compound (unit: mass %). The content of the inorganic layered compound was evaluated by ash analysis as described above.

[0121] As is clear from the results in Figure 5A, when the total amount of the resin composition is taken as 100 mass %, the inorganic layered compound content in the range of 3 to 15 mass % allows the gas barrier molded article sample to achieve good oxygen permeability. Furthermore, when the content of the inorganic layered compound is within this range, when the thickness of the gas barrier molded article is 100 μm, the oxygen permeability in an environment of 23°C and 60% relative humidity is 0.03 cc / m 2 Gas barrier properties of 10 ...

[0122] (Helium Permeability) The helium permeability of the gas barrier molded article sample according to this example was measured using differential pressure mass spectrometry.

[0123] First, the sample was heated in a vacuum at 50°C for 8 hours or more to degas the sample. 2 The helium permeability was measured under the following measurement conditions: primary side pressure: 100 kPa (absolute pressure), secondary side pressure: 0 kPa (vacuum), 40°C, and 0% RH (relative humidity). In measuring the helium permeability, the measured helium permeability was converted to a thickness of 100 μm, just like in measuring the oxygen permeability.

[0124] Figure 5B shows the relationship between helium permeability and the content of inorganic layered compound for a comparative sample of a gas barrier molded article made only of EVOH without containing inorganic layered compound (smectite), and four types of gas barrier molded article samples with different contents (addition rate, blending rate) of inorganic layered compound. In Figure 5B, the vertical axis represents helium permeability (unit: cc / m 2 The horizontal axis represents the content of the inorganic layered compound (unit: mass %). The content of the inorganic layered compound was evaluated by ash analysis as described above.

[0125] As is clear from the results in Figure 5B, when the total amount of the resin composition is taken as 100 mass %, the inorganic layered compound content in the range of 3 to 15 mass % allows the gas barrier molded article sample to achieve good helium permeability. Furthermore, when the content of the inorganic layered compound is within this range, when the thickness of the gas barrier molded article is 100 μm, the helium permeability in an environment of 40°C and 0% relative humidity is 55 cc / m 2 Gas barrier properties of 10 ...

[0126] The relationship between the measurement results of oxygen permeability shown in FIG. 5A and the measurement results of helium permeability shown in FIG. 5B is shown in FIG. 6. In FIG. 6, the vertical axis represents oxygen permeability (unit: cc / m 2 ·day·atm), and the horizontal axis is helium permeability (unit: cc / m 2 As is clear from the results in Figure 6, a relationship that can be considered to be substantially linear between the oxygen permeability and the helium permeability can be confirmed, and therefore it is determined that a proportional relationship exists between the oxygen permeability and the helium permeability.

[0127] (Additional Notes) Based on the descriptions of the above embodiments, the present specification discloses the following technologies: (Technology 1) A gas barrier molding formed from a resin composition containing a resin material and an inorganic filler, wherein the resin material is at least an ethylene-vinyl alcohol copolymer, the inorganic filler is at least an inorganic layered compound, the inorganic layered compound is dispersed in the resin material at a content in the range of 3 to 15 mass % when the total amount of the resin composition is taken as 100 mass %, and the gas barrier molding further contains agglomerated particles formed by agglomeration of the inorganic layered compound, and in the agglomerated particles, the resin material is interposed between adjacent particles of the inorganic layered compound in the thickness direction.

[0128] In the above-described configuration, in a gas barrier molding containing an ethylene-vinyl alcohol copolymer as a resin material and an inorganic layered compound as an inorganic filler, the content of the inorganic layered compound is adjusted to be within a predetermined range, and in addition, some of the inorganic layered compound aggregates to form aggregated particles with the resin material interposed between them.

[0129] According to conventional common technical knowledge, it has been thought that it is important for inorganic fillers, particularly inorganic layered compounds, to disperse as "primary particles" in a resin material without agglomerating in order to exhibit gas barrier properties. However, in the gas barrier molded article according to the present disclosure, as described above, a portion of the inorganic layered compound aggregates to form "aggregated particles" with the resin material interposed therebetween, and it has been revealed that this makes it possible to achieve even better gas barrier properties than before.

[0130] Therefore, according to the above-mentioned configuration, it is possible to realize even better gas barrier properties in a gas barrier molded article containing an ethylene-vinyl alcohol copolymer and an inorganic layered compound.

[0131] (Technology 2) The gas barrier molding according to Technology 1, wherein when the inorganic layered compound dispersed in the resin material without aggregating is defined as a non-aggregated particle, and the non-aggregated particle and the aggregated particle are collectively defined as an inorganic particle, the thickness of the resin material present between the adjacent inorganic particles is 100 nm or more and 1000 nm or less, and the thickness of the resin material interposed between the adjacent inorganic layered compound in the aggregating particle is 1 nm or more and 10 nm or less.

[0132] According to the above configuration, if the thickness of the resin material interposed between agglomerated particles, between agglomerated particles and non-agglomerated particles, or between non-agglomerated particles is within the range of 100 to 1000 nm, the inorganic particles (aggregated particles and non-agglomerated particles) are more favorably dispersed in the resin material, which is thought to result in a favorable "maze effect" due to the inorganic particles, making it possible to achieve favorable gas barrier properties.

[0133] Furthermore, 1 to 10 nm of resin material is interposed between the inorganic layered compounds that make up the aggregated particles. This is thought to create a favorable "maze effect" in the aggregated particles themselves. As a result, the synergistic effect of the favorable dispersion of the inorganic particles and the presence of the aggregated particles makes it possible to achieve even better gas barrier properties.

[0134] (Technology 3) The gas barrier molding according to Technology 1 or Technology 2, wherein when the agglomerated particles are divided into small agglomerated particles having a major axis of less than 0.2 μm, medium agglomerated particles having a major axis of 0.2 μm or more and 0.5 μm or less, and large agglomerated particles having a major axis of more than 0.5 μm, the content of the intermediate agglomerated particles is 37% or more and 60% or less.

[0135] According to the above-mentioned configuration, when agglomerated particles are classified into three types based on their size, it is believed that the content ratio of intermediate agglomerated particles within the above-mentioned range will produce the "maze effect" derived from the agglomerated particles more effectively, thereby enabling the gas barrier molded article to achieve even better gas barrier properties.

[0136] (Technology 4) The gas barrier molded article according to any one of Technology 1 to Technology 3, having a haze of 10% or more and 60% or less.

[0137] According to the above-described configuration, if the haze of the gas barrier molding falls within the above-described range, it can be considered that the inorganic layered compound is well dispersed in the resin material, or that the ethylene-vinyl alcohol copolymer constituting the resin material is well crystallized. The crystallization of the ethylene-vinyl alcohol copolymer, together with the presence of aggregated particles, is thought to contribute to gas barrier properties. Therefore, it is possible to achieve even better gas barrier properties in the gas barrier molding.

[0138] (Technology 5) The gas barrier molding according to any one of Technology 1 to Technology 4, wherein the maximum peak height attributable to the ethylene-vinyl alcohol copolymer in a diffraction pattern obtained by X-ray diffraction (XRD) is 5000 CPS or more.

[0139] According to the above-described configuration, it can be considered that the ethylene-vinyl alcohol copolymer constituting the resin material is well crystallized. The crystallization of the ethylene-vinyl alcohol copolymer, together with the presence of aggregated particles, is thought to contribute to gas barrier properties. Therefore, it is possible to achieve even better gas barrier properties in the gas barrier molded article.

[0140] (Technology 6) The gas barrier molding according to any one of Technology 1 to Technology 5, wherein particles having a diameter of 7 μm or more are observed on the surface.

[0141] According to the above-described configuration, if particles with a diameter of 7 μm or more are observed, it can be considered that the ethylene-vinyl alcohol copolymer constituting the resin material is well crystallized. The crystallization of the ethylene-vinyl alcohol copolymer, together with the presence of aggregated particles, is thought to contribute to gas barrier properties. Therefore, it is possible to achieve even better gas barrier properties in the gas barrier molded article.

[0142] (Technology 7) The number of the particles is 40,000 particles / cm 2 The gas barrier molding according to Technology 6, which is as described above.

[0143] According to the above-mentioned configuration, particles with a diameter of 7 μm or more are 40,000 pieces / cm 2If the above can be confirmed, it can be considered that the ethylene-vinyl alcohol copolymer constituting the resin material is crystallized more satisfactorily, and therefore it becomes possible to realize even better gas barrier properties in the gas barrier molded article.

[0144] (Technology 8) The gas barrier molding according to any one of Technology 1 to Technology 7, wherein the inorganic layered compound is smectite.

[0145] According to the above-mentioned configuration, if the inorganic layered compound is smectite, it is possible to achieve even better gas barrier properties in the gas barrier molded article.

[0146] (Technology 9) The gas barrier molding according to Technology 7, wherein the smectite is montmorillonite.

[0147] According to the above-mentioned configuration, if the smectite is montmorillonite, it is possible to achieve even better gas barrier properties in the gas barrier molded article.

[0148] (Technology 10) The gas barrier formed article according to Technology 8 or Technology 9, wherein the smectite contains at least sodium ions as interlayer cations.

[0149] According to the above-mentioned configuration, if the smectite contains at least sodium ions as interlayer cations, it is possible to achieve even better gas barrier properties.

[0150] (Technology 11) When the thickness of the gas barrier molded article is 100 μm, the oxygen permeability is 0.03 cc / m under an environment of 23° C. and a relative humidity of 60%. 2 The gas barrier molding according to any one of techniques 1 to 9, wherein the gas barrier density is 1000 kJ / cm² / day·atm or less.

[0151] According to the above-mentioned configuration, if the oxygen permeability under the above-mentioned conditions is equal to or less than the upper limit, the gas barrier molded article can achieve good gas barrier properties.

[0152] (Technology 12) When the thickness of the gas barrier molded article is 100 μm, the helium permeability is 55 cc / m under an environment of 40° C. and 0% relative humidity.2 The gas barrier molding according to any one of Techniques 1 to 9, wherein the gas barrier density is 1000 kJ / cm² / day·atm or less.

[0153] According to the above arrangement, if the helium permeability under the above conditions is equal to or less than the upper limit, the gas barrier molded article can achieve good gas barrier properties.

[0154] (Technology 13) A laminate comprising the gas barrier molded article according to any one of Technology 1 to Technology 12 as a gas barrier layer.

[0155] According to the above configuration, the laminate has a gas barrier layer that is a gas barrier shaped article containing aggregated particles of an inorganic layered compound. Therefore, the laminate not only achieves better gas barrier properties, but also improves the gas barrier properties through a synergistic effect with other layers, or achieves other functions in addition to the gas barrier properties.

[0156] It should be noted that the present disclosure is not limited to the description of the above-described embodiment. Various modifications of the present disclosure are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments or multiple modifications are also included in the technical scope of the present disclosure.

[0157] Furthermore, many modifications and other embodiments of the present invention will be apparent to those skilled in the art from the above description. Therefore, the above description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present invention. Details of the structure and / or function thereof may be substantially changed without departing from the spirit of the present invention.

[0158] The present invention can be widely and suitably used not only in the field of gas barrier moldings formed from resin compositions containing an ethylene-vinyl alcohol copolymer and an inorganic layered compound, but also in the field of laminates and the like that use the gas barrier moldings.

Claims

1. A gas barrier molding formed from a resin composition containing a resin material and an inorganic filler, wherein the resin material is at least an ethylene-vinyl alcohol copolymer, the inorganic filler is at least an inorganic layered compound, the inorganic layered compound is dispersed in the resin material at a content within a range of 3 to 15 mass % when the total amount of the resin composition is taken as 100 mass %, and the gas barrier molding further contains agglomerated particles formed by agglomeration of the inorganic layered compound, and in the agglomerated particles, the resin material is interposed between adjacent inorganic layered compounds in the thickness direction.

2. The gas barrier molding according to claim 1, wherein when the inorganic layered compound dispersed in the resin material without agglomeration is defined as a non-aggregated particle and the non-aggregated particle and the agglomerated particle are collectively defined as an inorganic particle, the thickness of the resin material present between adjacent inorganic particles is 100 nm or more and 1000 nm or less, and the thickness of the resin material interposed between adjacent inorganic layered compounds in the agglomerated particle is 1 nm or more and 10 nm or less.

3. The gas barrier molding according to claim 1, wherein when the agglomerated particles are divided into small agglomerated particles having a major axis of less than 0.2 μm, intermediate agglomerated particles having a major axis of 0.2 μm or more and 0.5 μm or less, and large agglomerated particles having a major axis of more than 0.5 μm, the content of the intermediate agglomerated particles is 37% or more and 60% or less.

4. The gas barrier molding according to claim 1, having a haze of 10% or more and 60% or less.

5. The gas barrier molding according to claim 1, wherein the maximum peak height attributable to the ethylene-vinyl alcohol copolymer in a diffraction pattern obtained by X-ray diffraction (XRD) is 5,000 CPS or more.

6. The gas barrier molding according to claim 1, wherein particles having a diameter of 7 μm or more are observed when the surface is observed.

7. The number of the particles is 40,000 / cm 2 The gas barrier molded article according to claim 6 .

8. The gas barrier molding according to claim 1, wherein the inorganic layered compound is a smectite.

9. The gas barrier molding according to claim 7, wherein the smectite is montmorillonite.

10. The gas barrier molding according to claim 8 or 9, wherein the smectite contains at least sodium ions as interlayer cations.

11. When the thickness of the gas barrier molded article is 100 μm, the oxygen permeability in an environment of 23° C. and relative humidity of 60% is 0.03 cc / m 2 The gas barrier molded article according to claim 1 , wherein the gas barrier pressure is 0.05 to 0.5 bar, and the gas barrier pressure is 0.05 to 0.5 bar.

12. When the thickness of the gas barrier molded article is 100 μm, the helium permeability in an environment of 40° C. and 0% relative humidity is 55 cc / m 2 The gas barrier molded article according to claim 1 , wherein the gas barrier pressure is 0.05 to 0.5 bar, and the gas barrier pressure is 0.05 to 0.5 bar.

13. A laminate comprising the gas barrier molded article according to any one of claims 1 to 9 as a gas barrier layer.

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